Furnace



March 27, 1934. g LANGMUER 4 1,952,923

FURNACE Driginal Filed July 50, 191 34 Fig.1.

Patented Mar. 27 1934 UNITED STATES PATENT oer-" ce FURNACE IrvingLangmuir, Schenectady, N. 12, assignor to General Electric Company, acorporation of New York 1929, Serial No. 371,316

2 Claims.

The present application is a division of my earlier application SerialNo. 729,185 for heating process and apparatus, filed July 30, .1924, inwhich is described and broadly claimed a new 5 methodand apparatus forcarrying out technical operations requiring high temperatures, such, forexample, as the fusion of metals.

In the practice of my invention the thermal dissociation of hydrogen athigh temperatures to form what I call atomic hydrogen in my paperspublished in the Journal of the American Chemical Society Vol. 36 (1914)page 1708 and Vol. 37 (1915) page 417, is utilized for industrialheating and metallurgical operations.

The dissociation of the ordinary form of molecular hydrogen to atomichydrogen consumes or renders latent a relatively large amount of heatwhich is again liberated when the atomic hydrogen is returned back toits molecular state.

In accordance with my invention I provide furnaces for carrying outheating operations wherein the latent heat of dissociation of hydrogenis utilized to convey heat efficiently from a heat source such as an arcto the work to be heated.

In one aspect the conversion of molecular hydrogen at the source of heatinto atomic hydrogen and the utilization of atomic hydrogen for heatingthe work is comparable to the conversion of water to steam and theutilization of the steam for heating accomplished by its" condensationto water. The active reducing character of atomic hydrogen, however, isa new property for which no analogy exists in the case of'steam andwhich renders atomic hydrogen as a source of heat of peculiar advantagein heating and fusing processes in which oxidation should be avoided.

In one aspect my invention comprises a furnace applicable to the fusionof metals wherein the dissociation of hydrogen is carried out by an 40electric arc, and atomic hydrogen is conveyed to the work by a currentor blast of molecular hydrogen. Such a furnace may be utilized forheating a charge which, because of its bulky nature, is not readilysusceptible to being heated efficiently by an ordinary arc. Metal scrap,for example,

may be melted advantageously in a furnace embodying my invention.Heating by atomic hydrogen also may be utilized for purposes other thanfusion.

Other novel features of my invention will be described in the followingspecification and pointed out with particularity in the appended claims.

In the accompanying drawing, Fig. 1 shows in perspective a scrap meltingfurnace embodying my invention; and Fig. 2 is a horizontal section ofthe same furnace.

The furnace shown somewhat diagrammatically in Figs. 1 and 2 may consistof fire-bricks and' comprise a fusion chamber 1 and a stack 2, intowhich scrap iron or other material to be melted is charged. The stack,to advantage, may widen or flare somewhat as it joins the fusionchamber.

The drawing shows two sets of heaters or torches projecting into thefurnace, but, of course, only one heater or a larger number may be usedaccording to circumstances. One heater projects into the fusion chamber1 where the molten metal accumulates and from which it is discharged bya spout 3 and the other heater projects into a horizontal passage 4,leading to the stack 2. Although both heaters cooperate to fuse thecharge, the heater projecting into the fusion chamber mainly serves toheat the collected molten material above its melting point.

The apparatus illustrated whereby hydrogen is dissociated comprisesarc-supporting electrodes 5, 6, held in hand-operated regulating devices7, 8, which in turn are supported upon plates 9, 10 set into the wall ofthe furnace. A stream of hydrogen, preferably dried hydrogen, isdirected through an are being operated between these electrodes andpasses from the are into contact with the work. The hydrogen is suppliedby a water-cooled tube 11 which projects through a base 12 containingducts (not shown) supplied with water or other cooling iiuid by thetubes 13.

contact with the arc is dissociated into atomic 10o hydrogen, thedissociation being accompanied by the absorption of heat from the arc.With an input of about 25 kilowatts and electrodes of about in diameter,separated about /8 to A", an arc voltage of about volts can be used. Theare is bowed out by the hydrogen blast. Much higher energy arcs andgreater lengths of arc can be used. For most commercial uses furnaces ofgreater power running into hundreds of kilowatts are preferable. Thearcs may be operated with either direct or alternating current. In theformer case a series resistance is necessary. In the latter case aseries reactance can be used or the energy may be derived from aconstant current transformer.

The arc assumes in hydrogen at. atmospheric pressure or at higherpressures a concentrated form, and operates at relatively high voltage.By blowing the arc outwardly by a transverse blast of hydrogen theoperating voltage may be raised to 600 volts or higher values. Theelectrodes remain substantially intact, or, in other words, are notconsumed by the arc.

Experiments indicate that the heat rendered latent by the dissociationof one gram of hydrogen is about 42,000 calories. As this latent heat ofdissociation is set free when the atomic hydrogen again combines orburns to form ordinary hydrogen after having left the are, thisrelatively large amount of heat is set free and is conveyed to the work.The dissociation of the hydrogen efliciently carries heat from the arcto the work, in this case represented by the metal scrap, which has arelatively large mass, whereas an electric are when playing directlyupon the work would heat only local parts of the mass. The hydrogen alsomaintains a reducing atmosphere, thereby preventing oxidation of thematerial being melted. Low pressure bathing hydrogen may be supplied tothe interior of the furnace by a conduit 15.

While I have shown and described a particular embodiment of myinvention, such modifications and variations are contemplated as fallwithin the scope of my invention which is set forth in the appendedclaims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. An electric furnace having in combination, a heating chamber,electrodes and means for maintaining an electric are between them, asource of hydrogen, means for sending a current of hydrogen fromsaid-source past said are so as to dissociate the hydrogen into itsatomic state and for delivering said dissociated hydrogen directly fromsaid are onto the, contents of the heating chamber without contact withthe walls of said chamber or any inlet passage.

2. An electric furnace having in combination, a heating chamber,tungsten electrodes and means for maintaining between them a high powerelectric arc, a source of hydrogen, means for sending a current ofhydrogen from said source past said arc so as to dissociate the hydrogeninto atomic hydrogen and for delivering said dissociated hydrogendirectly from said are onto the contents'of the heating chamber withoutcontact with the walls of said chamber or any inlet passage.

IRVING LANGMUIR.

CERTIFHEATE @F CORRECTlON.

Patent No. l, 952, 927.

March 27, 1934.

IRVING LANGMUIR.

it is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,line 30, for "accomplished" read accompanied; and line 59, for"fire-bricks" read fire-brick; and that the said Letters Patent shouldbe read with these corrections therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 15th day of May, A. D. 1934.

(Seal) Bryan M. Battey Acting Commissioner of Patents.

